# include <iostream>

using namespace std;
void test01(){
    string str ="abcdefg";
    string subStr=str.substr(1,3);
    cout<<"subStr="<<subStr<<endl;
    string email="hello@sina.com";
    int pos=email.find("@");
    string userName=email.substr(0,pos);
    cout<<"userName:"<<userName<<endl;

}
int main() {
test01();
    system("pause");
    return 0;
}
